1. Field of the Invention
The present invention relates to a telephone handset and, more particularly, to a telephone handset having a modular jack which is provided with an implementation for preventing electrostatic discharge.
2. Description of the Prior Art
A current trend in the telephones art is toward a telephone body and a handset which are interconnected by a coiled cord having modular plugs at opposite ends thereof. Specifically, as shown in FIG. 1, the handset of this type of telephone has a modulator jack 9 for accommodating a modular plug 8 which is fitted on one end of a coiled cord. To promote easy insertion and removal of the modular plug 8, the modular jack 9 has customarily been located in close proximity to a plug inlet 11 which is formed through a handset cover 10.
A modular jack having a specific construction is disclosed in U.S. Pat. No. 3,850,497, while a handset (telephone set) using such a modular jack is disclosed in U.S. Pat. No. 4,124,785. The modular jack 9 shown in FIG. 1 has an insulative case 12 in which conductors 13 are accommodated in a bent position to provide electrical contacts.
The bend of each conductor 13 is so positioned as to face outwardly without exception in order to facilitate the insertion of the modular plug 8. More specifically, the bend is extremely close to the outer periphery of the handset because the modular jack 9 is situated immediately inwardly of the opening 11. This brings about a serious problem inasmuch as the handset is to be held by hand. When one holds the handset, especially when one holds its portion adjacent to the opening 11 as we so often do, the static electricity from the human body is discharged to the contacts of the jack 9 and those of the plug 8. This introduces noise into the telephone circuit and often results in malfunctions. Further, the sweat and moisture on the palm of the hand is apt to short-circuit the contacts of the plug 8 and jack 9.
The plug 8 and jack 9 are fixed together by a locking mechanism in order to insure their continued electrical connection. For this purpose, the plug 8 has an elastic tongue or resilient leaf spring 82 which protrudes from the handset through the opening 11, as shown in FIG. 1. This gives rise to another problem that while one is talking on the telephone, the leaf spring or tongue 82 is apt to catch the person's finger resulting in the plug 8 being pulled out of the jack 9.